Well, I was trying to address them with my personal experiences, saying that for me, it doesn't work that way. My stats are higher on attack and non-roamers, so for me, my stats aren't inflated by roaming as you suggest. In fact, my stats are dragged down by roaming. But I do it anyway because it's fun. Killing five people in the first 10 seconds of the match, I love it. More than anything on the game. I love making someone ragequit the match, I guess that makes me cruel, I don't know, but it's satisfying.
Less anecdotal though, what I meant is that I feel that when roaming the risk is greater than the reward for roaming, as reflected by my stats on those characters. I don't disagree with your points on how roaming doesn't help in many cases (that's why win/loss ratio on dedicated roamers like Jager is actually lower too), but I think you seem to believe that roaming is easier than it is. Roamers do have more kill opportunities, but they also have more opportunities to be killed. Roamers should end up with higher killcounts, but not necessarily higher kill to death ratios.
Also you don't have to be a roamer to do the right thing to kill the enemy team. If you're pinned in from the windows on library and you know the left side window is clear, doing things like jumping onto the window and killing everyone sat on the ledge doesn't suddenly make you a roamer, that's what I mean, you can still get many of those 'surprise' scenarios on defense... obviously yes, if you're completely static then you won't do well on defense, but I don't think your helping your team all that much by doing so either.
Still, it's impossible to not respond anecdotaly here because all you and I have are our own experiences. Your initial post itself is anecdotal. I tried to use my stats as a demonstration to make my perspective less so, but it's still just one perspective all the same. I also managed to accidentally close chrome and I did have a larger post written up on the original one at first, but it disappeared.
Oh, I also find it funny that you seem to post in most of the OTs that I do. I guess we like the same games! I only keep up with 5 and the only 2 you are missing from of those are Digimon and Street Fighter